What Is Pulmonary Tuberculosis And How To Prevent Its Spread?

What is pulmonary tuberculosis?

Pulmonary tuberculosis is a form of Tuberculosis that affects the lungs which is caused by a bacteria called Mycobacterium Tuberculosis.

Pulmonary TB occurs when Mycobacterium tuberculosis primarily attacks the lungs. However, it can spread from there to other organs. Pulmonary TB is curable with an early diagnosis and antibiotic treatment.

Pulmonary TB spread widely as an epidemic during the 18th and 19th centuries in North America and Europe. After the discovery of antibiotics like streptomycin and especially isoniazid, along with improved living standards, doctors were better able to treat and control the spread of TB.

Since that time, TB has been in decline in most industrialized nations. However, TB remains in the top 10 causes of death worldwide, according to the World Health Organization (WHO), with an estimated 95% of TB diagnoses as well as TB-related deaths occur in developing countries.

That said, it’s important to protect yourself against TB. Over 9.6 million people have an active form of the disease, according to the American Lung Association (ALA). If left untreated, the disease can cause life-threatening complications like permanent lung damage.

What is latent TB?

Being exposed to M. tuberculosis does not necessarily mean you will get sick. Among the 2.5 billion people who carry the germ, most have latent TB.

People with latent TB aren’t contagious and have no symptoms because their immune system is protecting them from getting sick. But it is possible for latent TB to develop into active TB. Most people with the germ have up to a 15 percent lifetime risk of getting sick with TB. The risk can be far higher if you have conditions that compromise your immune system such as HIV infection. When you start showing symptoms, you may become contagious and have pulmonary TB.

If you’re at risk of being exposed to M. tuberculosis (for example, because you were born in a country where TB is common), you should talk to your doctor about being tested for latent TB infection and being treated if test results are positive.

What causes pulmonary TB?

TB is an infection caused by a type of bacteria called Mycobacterium tuberculosis (M. Tuberculosis).

About one-third of the world’s population is infected with this type of bacteria. However, only around 10–20 percent of people with this infection develop “active TB.”

A person who carries the bacteria but does not develop symptoms has “latent TB.” This is not contagious, but it can eventually develop into active TB, particularly if a person’s immune system becomes weakened from a condition such as HIV.

TB can become active when the immune system is unable to prevent the bacteria from multiplying. However, many people with latent TB never go on to develop active disease. A doctor can use a skin or blood test to check for the presence of M. tuberculosis.

What is the mode of transmission for Pulmonary TB?

People with active pulmonary TB exhale the bacteria in tiny water droplets when they cough, sneeze, or speak. These droplets travel through the air and a person can breathe them in.

However, an individual generally needs to be in prolonged close contact with someone who has active TB to contract the infection. A TB infection in a part of the body other than the lungs is not usually contagious.

  Risk factors for pulmonary TB.

Living with or having prolong close contact with infected person who has developed an active form of pulmonary TB is the highest risk of getting pulmonary TB. 

This includes being around family or friends with TB or working in places such as the following that often house people with TB:

nursing homes

hospitals

correctional facilities

shelters

group homes.

People also at risk for developing pulmonary TB disease are:

people who are immunocompromised, such as those living with HIV, undergoing chemotherapy, or taking chronic steroids

older adults

people who smoke

small children

people with an autoimmune disorder, such as lupus or rheumatoid arthritis

people with lifelong conditions, such as diabetes or kidney disease

people who inject drugs.

What are the symptoms of pulmonary TB?

Symptoms of TB can develop slowly and may vary. The main symptoms of pulmonary TB include:

a cough that lasts for at least 2-3 weeks

chest pain

coughing up sputum

coughing up blood

breathlessness.

More general symptoms of TB can include:

a loss of appetite

nausea and vomiting

weight loss

fatigue

fever and chills

night sweats.

People with latent TB do not have any symptoms or feel sick.

How is pulmonary TB diagnosed?

During examination, your doctor will:

conduct a physical exam to check for fluid in your lungs

ask about your medical history

schedule a chest X-ray

order a medical test to confirm pulmonary TB.

To diagnose pulmonary TB specifically, a doctor will ask a person to perform a strong cough and produce sputum up to three separate times. The doctor will send the samples to a laboratory. At the lab, a technician will examine the sputum under a microscope to identify TB bacteria.

In addition to this test, a doctor can also “culture” a sputum sample. This means they take a portion of the sputum sample and put it in a special material that makes TB bacteria grow. If TB bacteria grow, this is a positive culture.

Doctors can also order a polymerase chain reaction (PCR) assay to be performed. This tests the sputum for the presence of certain genes from the germs that cause TB.

During the physical exam, your doctor will check your lymph nodes for swelling and use a stethoscope to listen carefully to the sounds your lungs make while you breathe.

What are the  Complications of PulmonaryTuberculosis? 

The most common complications of pulmonary TB are:

Hemoptysis (coughing up blood)

Laryngitis (inflammation of the larynx)

Pleural effusion

Pneumothorax

Cor pulmonale

Ca bronchus

Endobronchitis

Aspergilloma

Enteritus

Miliary Tuberculosis

HIV related opportunistic infections.

Treatment for latent TB and pulmonary TB.

Treatment for latent TB is very important even if there is no symptoms of the disease because you can develop pulmonary TB disease in the future. You may only need one TB drug if you have latent TB.

If you have pulmonary TB, your doctor may prescribe several medicines. You’ll need to take these drugs for six months or longer for the best results.

The most common TB medicines are:

isoniazid

pyrazinamide

ethambutol (Myambutol)

rifampin (Rifadin)

Your doctor might recommend an approach called directly observed therapy (DOT) to ensure that you complete your treatment. Stopping treatment or skipping doses can make pulmonary TB resistant to medicines, leading to MDR-TB.

With DOT, a healthcare professional meets with you every day or several times a week to administer your medication so that you don’t have to remember to take it on your own.

If you aren’t on DOT, make a schedule for taking your medicines so that you don’t miss a dose. Here are some tips to help you remember to take your medicines:

_Take medicines at the same time every day.

_Make a note on your calendar each day to show that you’ve taken your medicine.

_Seek someone's help remind you to take your drugs every day.

_Keep your drugs in a pill organizer.

You won’t need to go to the hospital unless you’re unable to take the medication at home or have a bad reaction to the treatment.

What is multidrug-resistant TB?

Multi-drug resistant TB (MDR-TB) is TB that is resistant to the typical antibiotics used to treat the condition, which are isoniazid and rifampin. Some of the factors that contribute to MDR-TB include:

people who stopped treatment early

healthcare providers prescribing an incorrect drug to treat TB

people taking poor-quality medications.

According to WHO, improper prescribing is the leading cause of MDR-TB. However, it is possible a person who has not ever taken TB medications can have a strain that is drug-resistant.

People who develop MDR-TB also have fewer options for treatment. The second-line treatments can be expensive and take as long as two years. It is also possible for MDR-TB to develop even further into extensively drug-resistant TB (XDR-TB). This is why it’s important to finish your medications, even if you feel better before you finish your dosage.

  Outlook for  pulmonary TB

Pulmonary TB is curable with treatment, but if left untreated or not fully treated, the disease often causes life-threatening complications. Untreated pulmonary TB disease can lead to long-term damage to these parts of the body:

lungs

brain

liver

heart

spine.

Stopping the transmission of TB from one adult to another

Firstly there is a need to stop the transmission of TB from one adult to another.

How to prevent the spread of Pulmonary TB?

This is done through firstly, identifying people with active TB, and then curing them through the provision of drug treatment. With proper TB treatment someone with TB will very quickly not be infectious and so can no longer spread TB to others.

If someone is not on treatment, then precautions such as cough etiquette, must be taken to prevent TB spreading from one adult to another.

Anything which increases the number of people infected by each infectious person, such as ineffective treatment because of drug resistant pulmonary TB, reduces the overall effect of the main prevention efforts. The presence of Pulmonary TB and HIV infection together also increases the number of people infected by each infectious person. As a result it is then more likely that globally the number of people developing active pulmonary TB will increase rather than decrease.

Other TB prevention activities

There are several other TB prevention activities. This includes preventing people with latent TB from developing active and infectious TB disease.

TB infection control including the use of masks & respirators, which means preventing the transmission of TB in such settings as hospitals & prisons.

There is a vaccine for TB, but it makes only a small contribution to TB prevention. It does little to interrupt the transmission of TB among adult.

 Cough etiquette

TB is caused when a person breathes in TB bacteria that are in the air. So it is important that people with TB, who are not on effective treatment, do not release TB bacteria into the air when they cough.

Cough etiquette means that if you have pulmonary TB, or you might have it, then when you cough you should cover your mouth and nose with a tissue. You should put your used tissue in a dust bin. If you don't have a tissue then you should cough or sneeze into your upper sleeve or elbow. You should not cough into your hands. After you have coughed you should wash your hands.

 Prevention by using BCG vaccine

The vaccine called Bacillus Calmette-Guerin (BCG) was first developed in the 1920s. It is one of the most widely used of all current vaccines, and it reaches more than 80% of all new born children and infants in countries where it is part of the national childhood immunization programme. However, it is also one of the most variable vaccines in routine use.

The BCG vaccine has been shown to provide children with excellent protection against the disseminated forms of TB. However protection against pulmonary TB in adults is variable. Since most transmission originates from adult cases of pulmonary TB, the BCG vaccine is generally used to protect children, rather than to interrupt transmission among adults.

The BCG vaccine will often result in the person vaccinated having a positive result to a TB skin test.

 Pulmonary TB education

Health education is necessary for people with pulmonary TB. People with the infection need to know how to take their TB drugs properly. They also need to know how to make sure that they do not pass it on to other people. But pulmonary TB education is also necessary for the general public. The public needs to know basic information about it for a number of reasons including reducing the stigma still associated with pulmonary TB.

Treatment as TB prevention

Drug treatment for the prevention of TB, also known as chemoprophylaxis, can reduce the risk of a first episode of active pulmonary TB occurring in people with latent TB.  The treatment of latent TB is being used as a tool to try and eliminate TB in the United States.

Isoniazid is one of the drugs used to prevent latent TB from progressing to active TB or TB disease. Isoniazid is a cheap drug, but in a similar way to the use of the BCG vaccine, it is mainly used to protect individuals rather than to interrupt transmission between adults. This is because children rarely have infectious TB, and it is hard to administer isoniazid on a large scale to adults who do not have any symptoms. Taking isoniazid daily for six months is difficult in respect of adherence, and as a result many individuals who could benefit from the treatment, stop taking the drug before the end of the six month period.

There have also been concerns about the possible impact of TB treatment for prevention programmes on the emergence of drug resistance. However, a review of the scientific evidence has now shown that there is no need for this to be a concern. The benefit of isoniazid preventative therapy for people living with HIV, and who have, or may have had latent TB, has also recently been emphasized.

How to protect others?

People with latent TB aren’t contagious and can go about their day-to-day lives as usual.

But if you have pulmonary TB disease, you need to stay home and avoid close contact with others. Your doctor will tell you when you’re no longer contagious and can resume a regular routine.

Sources:

www.medicalnewstoday.com

www.healthline.com

www.mayoclinic.org